Silicone adhesive and preparation method thereof

Abstract

The present invention discloses a silicone adhesive comprising: a component A and a component B. Component A comprises, by weight, 60-70 parts vinyl silicone oil, 30-40 parts modified silicone resin, and 0.05-0.15 parts catalyst; and component B comprises, by weight, 60-70 parts vinyl silicone oil, 30-40 parts modified silicone resin, and 3-4 parts hydrogenated silicone oil. The present invention also discloses a method for preparing the silicone adhesive. The present invention exhibits excellent bonding strength and can tightly bond automotive plastic products.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to a silicone adhesive and a preparation method thereof. Background Art

[0002] Silicone adhesives offer excellent weather resistance, heat resistance, electrical insulation, flame retardancy, and hydrophobicity, and are currently widely used in electronics, defense, medicine, machinery, construction, and daily life. However, silicone adhesives also have drawbacks, such as poor adhesion, curing, and compatibility.

[0003] At present, the organic silicone adhesives used to bond plastic products on new energy vehicles often have the problem of low bonding strength between the organic silicone adhesive and the plastic after vulcanization, and are prone to debonding and falling off; and the amount of adhesive used is large, and the adhesive is too thick after application. After vulcanization, the overflowed part of the adhesive will turn white, affecting the appearance of the product. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a silicone adhesive and a preparation method thereof. The present invention has good bonding strength and can tightly bond automotive plastic products.

[0005] The present invention provides a silicone adhesive comprising: a component A and a component B, wherein the raw materials of the component A comprise, by weight, 60-70 parts of vinyl silicone oil, 30-40 parts of modified silicone resin, and 0.05-0.15 parts of a catalyst; and the raw materials of the component B comprise, by weight, 60-70 parts of vinyl silicone oil, 30-40 parts of modified silicone resin, and 3-4 parts of hydrogenated silicone oil.

[0006] Preferably, in the preparation process of the modified silica gel resin, γ-glycidyloxypropyltrimethoxysilane, diphenylsilanediol, methylvinyldimethoxysilane, and anion exchange resin are reacted in an inert gas atmosphere to obtain material A; then, in an inert gas atmosphere, material A is added to the dopamine solution to react to obtain the modified silica gel resin.

[0007] Preferably, the reaction is carried out at 60-70°C for 15-18h to obtain material A.

[0008] Preferably, the molar ratio of γ-glycidyloxypropyltrimethoxysilane, diphenylsilanediol, and methylvinyldimethoxysilane is 0.4-0.5:1:0.5-0.6.

[0009] Preferably, the anion exchange resin accounts for 6-8% of the total weight of gamma-glycidoxypropyltrimethoxysilane, diphenylsilanediol and methylvinyldimethoxysilane.

[0010] Preferably, the molar ratio of γ-glycidyloxypropyltrimethoxysilane to dopamine is 1:1-1.1.

[0011] Preferably, the modified silica gel resin is obtained by reacting at 60-70° C. for 30-36 hours.

[0012] Preferably, the pH of the dopamine solution is 8-8.5. The pH of the dopamine solution can be adjusted to 8-8.5 using 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0013] Preferably, the solvent of the dopamine solution is a mixture of N,N-dimethylformamide and propylene glycol methyl ether.

[0014] Preferably, the catalyst is chloroplatinic acid-divinyltetramethyldisiloxane.

[0015] The present invention also provides a method for preparing the above-mentioned silicone adhesive, comprising the following steps: mixing component A and component B in equal weights, and heating at 65-75° C. for 15-25 minutes to obtain the silicone adhesive.

[0016] Beneficial effects:

[0017] The present invention selects γ-glycidyloxypropyltrimethoxysilane, diphenylsilanediol, and methylvinyldimethoxysilane in an appropriate proportion to synthesize silica gel, introduces epoxy groups, and then reacts with primary amines in dopamine to introduce catechol groups into the silica gel, thereby greatly improving the adhesion and bonding strength of the silica gel. In addition, the γ-glycidyloxypropyltrimethoxysilane, diphenylsilanediol, and methylvinyldimethoxysilane are coordinated with each other in an appropriate proportion and combined with an appropriate amount of vinyl silicone oil and hydrogen-containing silicone oil, so that the adhesive can have a dense cross-linked network and good mechanical strength. Thus, the present invention can be tightly bonded to the plastic product, so that the adhesive has good bonding firmness after vulcanization, and the problem of debonding can be avoided. In addition, the present invention has good adhesion and requires a small amount of glue, which can avoid the problem of excessive thickness of the glue after coating and whitening of the overflowed adhesive after vulcanization, thereby improving the appearance of the product. DETAILED DESCRIPTION

[0018] Hereinafter, the technical solutions of the present invention will be described in detail through specific embodiments. However, it should be clearly stated that these embodiments are provided for illustration only and are not to be construed as limiting the scope of the present invention.

[0019] Example 1

[0020] A silicone adhesive, comprising: component A and component B, wherein the raw materials of component A include, by weight, 70 g of vinyl silicone oil, 30 g of modified silicone resin, and 0.15 g of chloroplatinic acid-divinyltetramethyldisiloxane; and the raw materials of component B include, by weight, 70 g of vinyl silicone oil, 30 g of modified silicone resin, and 4 g of hydrogenated silicone oil.

[0021] In the preparation process of the modified silica gel resin, 0.04 mol of γ-glycidyloxypropyltrimethoxysilane, 0.1 mol of diphenylsilanediol, and 0.06 mol of methylvinyldimethoxysilane were added to a flask, nitrogen was introduced, and the air was exhausted. Then, 2.34 g of anion exchange resin was added, and the temperature was raised to 60° C. to react for 18 hours. Then, the mixture was filtered, and the filtrate was evaporated under reduced pressure to remove volatile gases to obtain material A.

[0022] In a nitrogen atmosphere, 0.04 mol of dopamine was dissolved in a mixture of N,N-dimethylformamide and propylene glycol methyl ether (N,N-dimethylformamide and propylene glycol methyl ether in equal volume ratios), and then 1,5,7-triazabicyclo[4.4.0]dec-5-ene was added to adjust the pH to 8.5. Then, the above-mentioned material A was added and mixed. The temperature was adjusted to 60°C and the reaction was carried out for 36 hours. Then, a hydrochloric acid aqueous solution with a pH of 2 was added for precipitation treatment. The precipitate was collected and dried to obtain a modified silica gel resin.

[0023] The preparation method of the above-mentioned silicone adhesive comprises the following steps: mixing component A and component B in equal weights, and heating at 65° C. for 25 minutes to obtain the silicone adhesive.

[0024] Example 2

[0025] A silicone adhesive, comprising: component A and component B, wherein the raw materials of component A include, by weight, 60 g of vinyl silicone oil, 40 g of modified silicone resin, and 0.05 g of chloroplatinic acid-divinyltetramethyldisiloxane; and the raw materials of component B include, by weight, 60 g of vinyl silicone oil, 40 g of modified silicone resin, and 3 g of hydrogenated silicone oil.

[0026] In the preparation process of the modified silica gel resin, 0.05 mol of γ-glycidyloxypropyltrimethoxysilane, 0.1 mol of diphenylsilanediol, and 0.05 mol of methylvinyldimethoxysilane were added to a flask, nitrogen was introduced, and the air was exhausted. Then, 3.2 g of anion exchange resin was added, and the temperature was raised to 70°C for reaction for 15 hours. Then, the mixture was filtered, and the filtrate was evaporated under reduced pressure to remove volatile gases to obtain material A.

[0027] In a nitrogen atmosphere, 0.05 mol of dopamine was dissolved in a mixture of N,N-dimethylformamide and propylene glycol methyl ether (N,N-dimethylformamide and propylene glycol methyl ether in equal volume ratios), and then 1,5,7-triazabicyclo[4.4.0]dec-5-ene was added to adjust the pH to 8. Then, the above-mentioned material A was added and mixed. The temperature was adjusted to 70°C and the reaction was carried out for 30 hours. Then, a hydrochloric acid aqueous solution with a pH of 2 was added for precipitation treatment. The precipitate was collected and dried to obtain a modified silica gel resin.

[0028] The preparation method of the above-mentioned silicone adhesive comprises the following steps: mixing component A and component B in equal weights, and heating at 75° C. for 15 minutes to obtain the silicone adhesive.

[0029] Example 3

[0030] A silicone adhesive, comprising: a component A and a component B, wherein the raw materials of component A include, by weight, 65 g of vinyl silicone oil, 35 g of modified silicone resin, and 0.1 g of chloroplatinic acid-divinyltetramethyldisiloxane; and the raw materials of component B include, by weight, 65 g of vinyl silicone oil, 35 g of modified silicone resin, and 3.5 g of hydrogenated silicone oil.

[0031] In the preparation process of the modified silica gel resin, 0.045 mol of γ-glycidyloxypropyltrimethoxysilane, 0.1 mol of diphenylsilanediol, and 0.055 mol of methylvinyldimethoxysilane were added to a flask, nitrogen was introduced, and the air was exhausted. Then, 2.77 g of anion exchange resin was added, and the temperature was raised to 65° C. to react for 17 hours. Then, the mixture was filtered, and the filtrate was evaporated under reduced pressure to remove volatile gases to obtain material A.

[0032] In a nitrogen atmosphere, 0.045 mol of dopamine was dissolved in a mixture of N,N-dimethylformamide and propylene glycol methyl ether (N,N-dimethylformamide and propylene glycol methyl ether in equal volume ratios), and then 1,5,7-triazabicyclo[4.4.0]dec-5-ene was added to adjust the pH to 8.2. Then, the above-mentioned material A was added and mixed, and the temperature was adjusted to 65°C for 33 hours. Then, a hydrochloric acid aqueous solution with a pH of 2 was added for precipitation treatment. The precipitate was collected and dried to obtain a modified silica gel resin.

[0033] The preparation method of the above-mentioned silicone adhesive comprises the following steps: mixing component A and component B in equal weights, and heating at 70° C. for 20 minutes to obtain the silicone adhesive.

[0034] Comparative Example 1

[0035] The modified silicone resin was replaced with vinyl silicone oil, and the rest was the same as in Example 3.

[0036] Comparative Example 2

[0037] The vinyl silicone oil was replaced by modified silicone resin, and the rest was the same as in Example 3.

[0038] Comparative Example 3

[0039] The modified silica gel resin was replaced by material A in Example 3, and the rest was the same as in Example 3.

[0040] The adhesives prepared in Examples 1-3 and Comparative Examples 1-3 were tested for performance. Plastic products of the same shape were bonded using the adhesives prepared in Examples 1-3 and Comparative Examples 1-3. The adhesives were then observed for debonding and the presence of white deposits after vulcanization. The results are shown in Table 1.

[0041] The 180° peel strength was tested according to GB / T2790-1995; the tensile strength was tested according to GB / T 528-2009.

[0042] Table 1 Test results

[0043]

[0044]

[0045] It can be seen from Table 1 that the present invention has good bonding strength and mechanical properties for plastic products, good bonding firmness after vulcanization, low degumming rate; and no white attachments, which can improve the appearance of the product.

[0046] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A silicone adhesive, characterized in that: include: Component A and component B, wherein the raw materials of component A include, by weight, 60-70 parts of vinyl silicone oil, 30-40 parts of modified silicone resin, and 0.05-0.15 parts of catalyst; the raw materials of component B include, by weight, 60-70 parts of vinyl silicone oil, 30-40 parts of modified silicone resin, and 3-4 parts of hydrogenated silicone oil; In the preparation process of the modified silica gel resin, γ-glycidyloxypropyltrimethoxysilane, diphenylsilanediol, methylvinyldimethoxysilane, and anion exchange resin are reacted in an inert gas atmosphere to obtain material A; then, in an inert gas atmosphere, material A is added to a dopamine solution to react to obtain the modified silica gel resin; React at 60-70°C for 15-18h to obtain material A; The molar ratio of γ-glycidyloxypropyltrimethoxysilane, diphenylsilanediol, and methylvinyldimethoxysilane is 0.4-0.5:1:0.5-0.6; The pH value of the dopamine solution is 8-8.5; the solvent of the dopamine solution is a mixture of N,N-dimethylformamide and propylene glycol methyl ether in an equal volume ratio; and the pH value is adjusted to 8-8.5 using 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

2. The silicone adhesive according to claim 1, characterized in that: The anion exchange resin accounts for 6-8% of the total weight of gamma-glycidoxypropyltrimethoxysilane, diphenylsilanediol and methylvinyldimethoxysilane.

3. The silicone adhesive according to claim 1, characterized in that: The molar ratio of γ-glycidyloxypropyltrimethoxysilane to dopamine is 1:1-1.

1.

4. The silicone adhesive according to claim 1, characterized in that: The reaction was carried out at 60-70°C for 30-36 hours to obtain a modified silica gel resin.

5. The silicone adhesive according to claim 1, characterized in that: The catalyst is chloroplatinic acid-divinyltetramethyldisiloxane.

6. A method for preparing the silicone adhesive according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: mixing component A and component B by weight, and heating at 65-75° C. for 15-25 minutes to obtain a silicone adhesive.

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